Labour leader David Shearer is set to put his leadership to the vote at an urgent caucus meeting tomorrow.

Shearer is expected to get 100 per cent backing from his caucus after rival David Cunliffe confirmed he would endorse Shearer for now.

But Cunliffe is refusing rule out a leadership tilt in February, meaning he is certain to be demoted by Shearer. Some of his supporters could also face demotion.

Senior Whip Chris Hipkins today confirmed Shearer had called a meeting so caucus could vote to endorse him as leader of the Labour party.

The vote would be held by secret ballot but the result would be made public.

The meeting comes as Cunliffe faces rising anger within the Labour caucus after failing to endorse Shearer's leadership at a tumultuous Labour Party conference at the weekend.

Hipkins today said Cunliffe's undermining of Labour's collective team effort "makes it very difficult for him tocontinue in a senior role within [our] team".

"At a time when we should be focused on getting out there holding the National Government to account and selling our policies and our message David Cunliffe has been working in the shadows to undermine the current leader and prepare for a leadership challenge. That's unacceptable.

"If David Cunliffe wants to challenge for the leadership he should come out of the shadows and get on with it..... it is totally unacceptable to say I'll support David Shearer for now while I work over the summer break to destabilise the leadership and get the numbers to move against him in February. If he is going to challenge for the leadership he needs to do it now."

In his speech yesterday, Shearer outlined promised reforms to economic policy, including a capital gains tax and changes to allow the Reserve Bank to target a lower exchange rate, and plans to launch the biggest house-building programme in 50 years.

It would put 100,000 families into new, affordable homes within 10 years.